1. Field of the Invention
This invention relates to inductive pickup clips, and more particularly to an inductive pickup clip whose ferrite core portions are extremely resistant to breakage due to the spring loading thereof and the manner in which the clip is closed by the user, as will be more particularly described hereinafter.
2. Description of the Prior Art
As is well known to those skilled in the art, the ferrite cores which are typically found in inductive pickup clips are extremely fragile, and thus susceptible to chipping and/or breakage during use. One common design for an inductive pickup clip is disclosed in U.S. Pat. No. 4,005,380 granted Jan. 25, 1977, to Heilmann et al. The Heilmann clip is generally of the configuration of a clothespin and comprises two members hinged together in the middle, the jaw ends of which are maintained normally closed by a spring under tension. Within the jaws of the device are mounted ferrite core halves which are brought into contact under the urging of said spring when the handle portions of the members are released. Such a device is normally susceptible to breakage of the ferrite cores since if the handles are squeezed together and then suddenly released the spring urges the jaws violently together, thereby chipping or breaking the cores. The Heilmann device attempts to solve this breakage problem by first mounting each core portion in a plastic support and then spring loading each plastic support/core portion assembly within its respective jaw.
The Heilmann device is unduly complex and costly due to the necessity for a separate plastic support for each core portion. In addition, this device is inconvenient and possibly dangerous to use since its handles may entangle other wires in the vicinity during use. This device is also inconvenient to use for the reason that the jaws must be held manually open with the handles against the tension of the spring which normally urges the jaws together, until the device can be clamped on the desired wire.
Another approach is taken by U.S. Pat. No. 3,475,682, granted Oct. 28, 1969 to Peek et al. In this device, one core portion is carried by a telescoping body portion. Although the core portions in the Peek device are unlikely to break during use, due to the fact that the core portions are aligned by longitudinally extending one core portion, it is possible that an undesirable air gap will exist between the core portions when they are aligned or that they will scratch or mar each other as they slide over one another, thereby rendering it likely that the device will have a reduced sensitivity and reliability.